In the modified version of the sharing games used in the new study, rather than choosing among a wide range of possible divisions, the first player could choose only between two divisions: equal, and a “selfish” division favoring the proposing player. This choice was presented in the form of two colored tokens that the first player would have to choose between, and which later could be exchanged for the actual rewards: food for the chimps, and stickers for the children, who were aged 2 to 7 years.